Re: Proportional duration and cross-staff notation

[Lib Lists]

On Tue, 30 May 2023 at 13:44, Leo Correia de Verdier
<leo.correia.de.verdier@gmail.com> wrote:
>
> But I have probably understood it wrong, because in that case I cannot see 
> what’s wrong with the default spacing...

Here is what I think it's wrong (see attached pdf, both scores made
with default spacing):
In the first score the spacing is correct.
In the second score the beaming affects the spacing.

As a reference, see the example 3b here
http://matthewmaslanka.blogspot.com/2009/08/optical-note-spacing.html
and a reproduction of the same example done with Lilypond in 2016 that
shows the same problem (even though Lilypond's spacing is very good in
many situations): https://notat.io/viewtopic.php?t=158&start=10

It seems to me that while Lilypond works very well with cross-staff
beaming when there's a single beam and same durations, there's a
problem when the cross-staff beam is interrupted (but the notes have
the same durations).

Here is the .ly if someone wants to experiment.

\version "2.25.5"

up = { \change Staff = "up"  \stemDown} %\revert NoteColumn.X-offset }
down = { \change Staff = "down" \stemUp}% \temporary\override
NoteColumn.X-offset = #-1.2 }

\score {
  \new PianoStaff  <<

    \new Staff = "up"  {
      \time 12/8
      \clef bass
      \new Voice { s1. s1. }
    }

    \new Staff = "down" {
      \override Beam.positions = #'( 6 . 6 )
      \clef bass
      \down b8[ c'  \up c' b
      \down b8  \up c' b
      \down c'  \up c'
      \down b8  \up c' b
      \down b8 c'  \up c' b
      \down b8  \up c' b
      \down c'  \up c'
      \down b8  \up c' b]
    }

  >>

  \layout {
    \context {
      \Score
      %proportionalNotationDuration = #(ly:make-moment 1/12)
      %\override SpacingSpanner.uniform-stretching = ##t
      %\override SpacingSpanner.strict-note-spacing = ##f
      %\consists "Grid_line_span_engraver"
    }
    \context {
      \Staff
      %\consists "Grid_point_engraver"
      %gridInterval = #(ly:make-moment 1/24)
      \override Beam.positions = #'( 6 . 6 )
      %\override NoteSpacing.stem-spacing-correction = #-2
    }
  }
}

\score {
  \new PianoStaff  <<

    \new Staff = "up"  {
      \time 12/8
      \clef bass
      \new Voice { s1. s1. }
    }

    \new Staff = "down" {
      \override Beam.positions = #'( 6 . 6 )
      \clef bass
      \down b8[ c'  \up c' b]
      \down b8[  \up c' b]
      \down c'[  \up c']
      \down b8[  \up c' b]
      \down b8[ c'  \up c' b]
      \down b8[  \up c' b]
      \down c'[  \up c']
      \down b8[  \up c' b]
    }

  >>

  \layout {
    \context {
      \Score
      %proportionalNotationDuration = #(ly:make-moment 1/12)
      %\override SpacingSpanner.uniform-stretching = ##t
      %\override SpacingSpanner.strict-note-spacing = ##f
      %\consists "Grid_line_span_engraver"
    }
    \context {
      \Staff
      %\consists "Grid_point_engraver"
      %gridInterval = #(ly:make-moment 1/24)
      \override Beam.positions = #'( 6 . 6 )
      %\override NoteSpacing.stem-spacing-correction = #-2
    }
  }
}

2305301447_LILYPOND_Der_Zauberlehrling_fragment_003-crop-small.pdf
Description: Adobe PDF document